WO2001056791A1

WO2001056791A1 - Device for supplying dampening water in offset printing machines

Info

Publication number: WO2001056791A1
Application number: PCT/KR2001/000095
Authority: WO
Inventors: Sueng Kook Han
Original assignee: Sueng Kook Han
Priority date: 2000-02-03
Filing date: 2001-01-19
Publication date: 2001-08-09
Also published as: AU2890801A; KR20010077966A

Abstract

A dampening water supplying device uses a thermoelement to control a temperature of a dampening water used in a printer. The dampening water supplying device includes a supplying pan mounted on the printer for holding the dampening water, and a thermoelemnt mounted on the supplying pan for thermoelectrically cooling or heating the dampening water. A polarity of the thermoelement is altered according to a temperature of the dampening water detected by the thermoelement, or according to a demand of a user. Accordingly, without a cooler, the temperature of the dampening water can be controlled accurately. Also, since the cooler, which uses refrigerant, is omitted, the device becomes more environment-friendly.

Description

DEVICE FOR SUPPLYING DAMPENING WATER IN OFFSET PRINTING

MACHINES

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for supplying dampening water in

offset printing machines, and more particularly, to a device for supplying dampening

water in offset printing machines for controlling a temperature of the dampening water

used in the offset printing machines and supplying the dampening water.

2. Description of the Related Art

Generally, a principle of an offset printing machine is that the printing is

performed by using a repelling force between water and oil. A pre-sensitized plate of

the offset printing machine is treated specially to have a hydrophilic non-image area and

an oleophilic printing area, thereby allowing the oleophilic printing area to be printed

with ink selectively. The ink on the oleophilic printing area is transferred to a blanket

and then is transferred to paper sheet.

Here, water that provides the non-image area with hydrophilicity thus prevents

the non-image area from being printed with the ink is called dampening water. The

dampening water has acidity, neutrality, or alkalinity therein according to the pH. At the present time, the dampening water having the acidity is used almost for the commercial

printing, while the dampening water having the alkalinity is used mainly for the

newspaper printing.

It is essential to supply the dampening water in an offset printing operation.

The dampening water is generally comprised of concentrated fountain solution, water,

and isopropyl alcohol (IPA).

Respective proportions of the concentrated fountain solution, the water, and the

isopropyl alcohol in the dampening water depend on a dampening method. For a

dampening method that uses a continuous water supply method, the dampening water is

comprised of the concentrated fountain solution of 1-5%, the water of 80-95%, and the

isopropyl alcohol of 20%.

It is ordinary to cool the dampening water to about 10~15°C to be used in the

printing machine, but a user may control a temperature thereof in the range of from 5°C

to 20°C depending on various variables such as types of the printing machine, an

environmental temperature, kinds of ink, kinds of printing material, a speed of the

printing machine, components of the dampening water, and etc.

FIG. 1 shows a conventional device for supplying dampening water in an offset

printing machine. As shown in FIG. 1, in a general offset printing machine, a printing plate 1 is rolled on a plate cylinder 2, and several ink rollers 5 are in contacts with the

plate cylinder 2 for completely mixing ink and supplying the mixed ink at a constant

rate.

The ink transferred to the plate cylinder 2 by the ink rollers 5 is transferred to a

blanket cylinder 3 and then is printed on printing paper 7 which passes between the

blanket cylinder 3 and a impression cylinder 4. The dampening water is supplied to the

plate cylinder 2 from a supplying pan 20 through a plurality of rollers including a

dampening roller 6.

A continuous printing operation causes the dampening water to be

contaminated and even deteriorated by paper dust and a remainder of ink. Also, heat is

generated by friction between the rollers, increasing the temperature of the dampening

water. Accordingly, the temperature of the dampening water has to be kept low to obtain

the clean printing quality for a long time.

Meanwhile, in order to decrease the temperature of the dampening water, a

conventional offset printing machine circulates the dampening water through the

supplying pan 20 and a storing tank 10 according to a dampening water circulating

method. Also, a cooler 12 using a refrigerant such as the CFC or the like is separately

disposed at the storing tank 10 for cooling the dampening water. According to the cooling method for the conventional device for supplying

dampening water as described above, since the cooler 12 separately attached uses the

refrigerant such as the CFC, which causes ozone layer destruction, there is a problem of

environmental pollution.

A refrigerant that less pollutes the environment may be used to solve the above

problem, however there is a problem of increased cost for purchasing the refrigerant.

Also, since the cooler 12 is required to have a compressor, a heat changer, and etc, there

are problems such as increased volume of the device for supplying dampening water

and noise and vibration of the compressor.

Meanwhile, some devices for supplying dampening water have the supplying

pan only, without a dampening water circulating device and a storing tank. In this case,

since there is no cooler or circulating device, ice is temporarily put into the supplying

pan to decrease the temperature of the dampening water. However, it is difficult to

timely compensate for the temperature change of the dampening water and to maintain

the dampening water at a proper temperature.

Also, a device for supplying dampening water for a compact offset printing

machine is provided with only a supplying pan, without a dampening water circulating

device and a storing tank. Due to restriction on space and amount of the dampening water, a dampening water circulating device and a cooler using the CFC refrigerant

cannot be additionally provided to cool the dampening water. Thus, when an

environmental temperature becomes high, it is difficult to maintain the proper

temperature of the dampening water and thus to obtain a stable printing quality.

SUMMARY OF THE INVENTON

Accordingly, the technical goal and the object of the present invention is to

solve the above-described problems of a conventional device for supplying dampening

water in an offset printing machine, and to provide a device for supplying dampening

water in an offset printing machine which has a simplified structure and is capable of

controlling the temperature precisely.

The above object of the present invention is achieved by providing a device for

supplying dampening water in an offset printing machine according to the present

invention, which comprises a supplying pan for holding dampening water and a

thermoelement disposed on the supplying pan for thermoelectrically cooling or heating

the dampening water.

Here, the thermoelement is disposed on a bottom and/or a side of the supplying

pan. Also, at one side of the thermoelement, a heat sink is disposed for cooling the theremoelement. At one side of the heat sink, a blowing fan is disposed for escalating

heat exchange at the heat sink.

According to another embodiment of method for cooling the thermoelement,

the device for supplying dampening water further comprises a first heat element

disposed at one side of the thermoelement and a second heat element disposed at a

predetermined position of an interior or an exterior of the printing machine, the first

heat element being connected to the second heat element via a heat pipe.

Preferably, the first heat element is the heat pipe embedded heat sink. The

device for supplying dampening water further comprises a blowing fan disposed at one

side of the second heat element, for escalating heat exchange at the second heat element.

The above object of the present invention is also achieved by providing a

device for supplying dampening water in an offset printing machine comprising a

supplying pan for holding dampening water and a storing tank connected to the

supplying pan through a dampening water circulating device, wherein a thermoelement

is disposed on the supplying pan and/or the storing tank for thermoelectrically cooling

or heating the dampening water.

Here, the thermoelement is disposed on a bottom and/or a side of the supplying

pan and/or the storing tank. Also, preferably, the device for supplying dampening water further comprises a heat sink disposed at one side of the thermoelement for cooling the

thermoelement and a blowing fan disposed at one side of the heat sink for escalating

heat exchange at the heat sink;

Also, according to another embodiment of a method for cooling the

thermoelement, the device for supplying dampening water further comprises a first heat

element disposed at one side of the thermoelement and a second heat element disposed

at a predetermined position of an interior or an exterior of the printing machine, the first

heat element being connected to the second heat element via a heat pipe,.

Preferably, the first heat element is the heat pipe embedded heat sink. The

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a conventional device for supplying dampening

water;

FIG. 2 is a view showing a device for supplying dampening water according to

a first embodiment of the present invention;

FIG. 3 is a view showing a device for supplying dampening water according to a second embodiment of the present invention;

FIG. 4 is an enlarged view showing a supplying pan and surroundings of the

supplying pan of the device for supplying dampening water of FIGS. 2 and 3 in detail;

FIG. 5 is a view showing a structure cooling a thermoelement according to

another embodiment of the present invention; and

FIG. 6 is a circuit diagram of a thermoelement applied to the preferred

embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, preferred embodiments of the present invention will be described

in greater detail with reference to the accompanying drawings. The components

identical to the same of the prior art are given the same reference symbols, and detail

descriptions thereof are omitted.

FIG. 2 shows a device for supplying dampening water according to a first

embodiment of the present invention. As shown in FIG. 2, the device for supplying

dampening water according to the first embodiment of the present invention includes a

supplying pan 20, a thermoelement 40, and a control section 60.

The supplying pan 20 is disposed at a predetermined position of an interior of a printing machine for holding dampening water. The thermoelement 40 is disposed on

the supplying pan 20 for thermoelectrically cooling or heating the dampening water.

The control section 60 controls an operation of the thermoelement 20.

The thermoelement 40 is disposed on a bottom of the supplying pan 20. The

control section 60 may be a switch that is switched on/off according to a user's need, or

simple forms of the thermoelement such as a bimetal that is on/off controlled within a

predetermined range of temperature.

Also, the control section 60 may include a sensor for detecting a temperature of

the dampening water in the supplying pan 20. In this case, the control section 60 may

include a micom to automatically operate the thermoelement 20 according to the

temperature that is pre-set by the user.

The control section 60 can be constructed by various methods and a method for

constructing the control section 60 is not limited to the above example only. The device

for supplying dampening water of FIG. 2 can be employed in a compact offset printing

machine, in which the storage of the dampening water is small.

FIG. 3 shows a device for supplying dampening water according to a second

embodiment of the present invention. As shown in FIG. 3, the device for supplying

dampening water according to the second embodiment of the present invention includes a storing tank 10, a supplying pan 20, a thermoelement 40, and a control section 60.

The storing tank 10 is separately disposed at an exterior of the printing

machine. The supplying pan 20 is disposed at a predetermined position of an interior of

the printing machine. The storing tank 10 and the supplying pan 20 are connected to

each other through a circulating path 30.

A pump 11 is disposed at a link portion of the storing tank 10 and the

circulating path 30. The thermoelement 40 is disposed on the supplying pan 20 for

cooling or heating the dampening water. The thermoelement 40 is disposed on a bottom

of the supplying pan 20.

As described, according to the first embodiment of the present invention, the

control section 60 can be constructed by various methods and a method for constructing

the control section 60 is not limited to the above example only. The device for supplying

dampening water of FIG. 3 can be employed in a middle/large-sized offset printing

machine, in which the storage of the dampening water is large.

FIG. 4 is an enlarged view showing the supplying pan 20 and surroundings of

the supplying pan 20 in the device for supplying dampening water of FIGS. 2 and 3 in

detail. As shown in FIG. 4, the thermoelement 40 is disposed on the bottom of the

supplying pan 20. A temperature sensor 50 is disposed in the supplying pan 20 for detecting the temperature of the dampening water.

On a lower surface of a bottom of the thermoelement 40, a heat sink 41 and a

blowing fan 42 are disposed for an efficient heat exchange between the thermoelement

40 and the ambient air. Preferably, the supplying pan 20 is made of material of high heat

conductivity for a more efficient heat exchange with the thermoelement 40. Also, the

others, except for contacting surface with the thermoelement 40, are preferably

insulated against the heat.

At the heat sink 41, a plurality of fins 41a is formed for increasing the

efficiency of heat discharge. Also, an inlet hole 21 and an outlet hole 22 are formed in

the supplying pan 20 (a simple supplying pan without the inlet hole and the outlet hole

may also be used). The locations of the inlet hole 21 and the outlet hole 22 are not

limited to the locations as shown.

The dampening water supplied from the storing tank 10 by the pump 11 flows

into the supplying pan 20 through the inlet hole 21. When the water level in the

supplying pan 20 exceeds a predetermined limit, the dampening water flows out of the

supplying pan 20 and flows back into the storing tank 20 through the outlet hole 22.

To an exterior surface of the supplying pan 20, a heat insulating element 23 is

attached for preventing the heat exchange at the components other than the contacting surface with the thermoelement 40 with the ambient air. The heat insulating element 23

may be a Cork or a Styrofoam.

The heat insulating element 23 attached to the supplying pan 20 increases a

cooling efficiency of the thermoelement 40 and prevents water droplets from being

produced on the exterior surface of the supplying pan 20 during the cooling of the

dampening water.

Meanwhile, due to presence of the fins 41a and the blowing fan 42, a method

for cooling the thermoelement 40 as shown in FIG. 4 requires a considerable space.

This problem gets worse, as the heat emission of the thermoelement 40 goes up. Thus, if

there is restriction on an inner space of the printing machine regardless of types of the

printing machines, it is difficult to achieve the method for cooling the thermoelement 40.

FIG. 5 shows a structure cooling the thermoelement 40 according to another

embodiment of the present invention, which is applied to the case that there is

restriction on the space. As shown in FIG. 5, a first heat element 71 without the fins is

disposed on a lower surface of a bottom of the thermoelement 40.

The first heat element 71 may be a heat pipe 73 imbedded heat sink, the heat

pipe 73 is commercialized under the name of the so-called "heat superconduction pipe".

The first heat element 71 is connected via the heat pipe 73 to a second heat element 72 that is disposed at a predetermined position of an interior or an exterior of the printing

machine.

The second heat element 72 includes a plurality of fins 72a. The blowing fan

42 is disposed on one side of the second heat element 72 to escalate heat exchange at

the second heat element 72. Accordingly, since there is no need for the fins 72a and the

blowing fan 42 of relatively large size to be disposed adjacent to the supplying pan 20,

there is an advantage in terms of ensuring a space.

FIG. 6 is a circuit diagram showing the thermoelement 40 employed according

to the above embodiments of the present invention. The thermoelement 40 uses the

Peltier effect. The thermoelement 40 includes a semiconductor of P type 43 and a

semiconductor of N type 44, as shown in FIG. 6.

Certain sides of the semiconductor of P type 43 and the semiconductor of N

type 44 are connected to a first contact point 45, while the opposite sides thereof are

respectively connected to two second contact points 46 and 47 that are spaced apart

from each other to be insulated. FIG. 6 shows a circuit diagram of when the

thermoelement 40 cooling the dampening water. As shown in FIG. 6, a positive pole of

a power source 48 is connected to the second contact point 47 at the semiconductor of N

type 44, while a negative pole of the power source 48 is connected to the second contact point 46 at the semiconductor of P type 43.

Meanwhile, the first contact point 45 is connected to the supplying pan 20,

while the second contact points 46 and 47 are connected to the heat sink 41 or 71. Here,

if the DC voltage is supplied, an endothermic operation is carried out at the first contact

point 45, i.e., an electron, that absorbs heat energy from a periphery thereof, moves into

the semiconductor of N type 44, while an exothermic operation is carried out at the

second contact points 46 and 47 due to heat energy discharge by the electron.

Accordingly, the dampening water in the supplying pan 20 is cooled.

The dampening water in the supplying pan 20 is heated by the thermoelement

40 in a manner that a polarity of the power source 48 is altered by a generally known

switching circuit so that the positive pole and the negative pole of the power source 48

are respectively connected to the second contact point 46 of the semiconductor of P type

43 and the second contact point 47 of the semiconductor of N type 44. In this state, the

endothermic operation is carried out at the second contact points 46 and 47 and the

exothermic operation is carried out at the first contact point 45.

According to the detection made by the temperature sensor 50, it is determined

whether the dampening water needs the cooling or the heating. Then, the polarity of the

power source 48 is altered, and electricity current is supplied to the thermoelement 40 to the desired temperature of the dampening water. Accordingly, the temperature of the

dampening water can be controlled precisely.

Although the thermoelement 40 is disposed on the bottom of the supplying pan

20 in the above-described embodiments, it is possible that the thermoelement 40 is

disposed on a side of the supplying pan 20 or both the bottom and the side of the

supplying pan 20.

Also, the thermoelement 40 is disposed on a bottom and/or a side of the storing

tank 10 to control the temperature of the dampening water. Further, the thermoelement

40 may be disposed on both the supplying pan 20 and the storing tank 10.

According to the device for supplying dampening water in the offset printing

machine in accordance with the present invention as described, without having to

separately attach the cooler 12 to the device for supplying dampening water, the

thermoelement 40 is directly attached to the supplying pan 20 or the storing tank 10 to

control the temperature of the dampening water.

Accordingly, a structure of the device for supplying dampening water can be

simplified and the problem of noise and vibration from the compressor of the cooler 12

is solved. Also, since the refrigerant is not required, the device does not cause the

environmental pollution. Since the dampening water is easily cooled or heated by altering the polarity of the power source 48 of the theremoelement 40, it is possible to

precisely control the temperature of the dampening water.

Although the preferred embodiments of the present invention have been shown

and described, it will be appreciated by those skilled in the art that changes may be

made in these embodiments without departing from the principles and sprit of the

invention, scope of which is defined in the claims and their equivalents.

Claims

What is claimed is:

1. A device for supplying dampening water in an offset printing machine

comprising:

a supplying pan for holding dampening water; and

a thermoelement disposed on the supplying pan for thermoelectrically cooling

or heating the dampening water.

2. The device of claim 1, wherein the thermoelement is disposed on a bottom

and/or a side of the supplying pan.

3. The device of claim 1, further comprising a heat sink and a blowing fan

disposed at one side of the thermoelement, the blowing fan for escalating heat exchange

at the heat sink.

4. The device of claim 1, further comprising:

a first heat element disposed at one side of the thermoelement; and

a second heat element disposed at a predetermined position of an interior or an

exterior of the printing machine, the first heat element being connected to the second heat element via a heat

pipe.

5. The device of claim 4, wherein the first heat element is the heat pipe

embedded heat sink.

6. The device of claim 4, further comprising a blowing fan disposed at one side

of the second heat element, for escalating heat exchange at the second heat element.

7. In a device for supplying dampening water in an offset printing machine

comprising a supplying pan for holding dampening water and a storing tank connected

to the supplying pan through a dampening water circulating device, the device further

comprising a thermoelement disposed on the supplying pan and/or the storing tank for

thermoelectrically cooling or heating the dampening water.

8. The device of claim 7, wherein the thermoelement is disposed on a bottom

and/or a side of the supplying pan and/or the storing tank.

9. The device of claim 7, further comprising a heat sink and a blowing fan

at the heat sink.

10. The device of claim 7, further comprising:

a first heat element disposed at one side of the thermoelement; and

a second heat element disposed at a predetermined position of an interior or an

exterior of the printing machine,

the first heat element being connected to the second heat element via a heat

pipe.

11. The device of claim 10, wherein the first heat element is the heat pipe

embedded heat sink.

12. The device of claim 10, further comprising a blowing fan disposed at one

side of the second heat element, for escalating heat exchange at the second heat element. AMEN DED CL AIMS

, " e r ed by the Internatioi.al Bureau on 20 hπu 2001 (20.06.01 ); oi i .. .. I , 5, o,V, 1 1 and 12 amend.-, _: .₀:-:- - . ' '.ns 4 and 10 cancelled; other claims unchanged (3 pages)]

1. A device for supplying dampening water in an offset printing machine

comprising:

a supplying pan for holding dampening water;

a thermoelement disposed on the supplying pan for thermoelectrically cooling

or heating the dampening water;

a first heat element disposed at one side of the thermoelement; and

a second heat element disposed at a predetermined position of an interior or an

exterior of the printing machine,

the first heat element being connected to the second heat element via a heat

pipe.

2. The device of claim 1, wherein the thermoelement is disposed on a bottom

and/or a side of the supplying pan.

3. The device of claim 1, further comprising a heat sink and a blowing fan

at the heat sink.

5. The device of claim 1, wherein the first heat element is the heat pipe

embedded heat sink.

6. The device of claim 1, further comprising a blowing fan disposed at one side

7. In a device for supplying dampening water in an offset printing machine

comprising:

a thermoelement disposed on the supplying pan and/or the storing tank for

thermoelectrically cooling or heating the dampening water;

a first heat element disposed at one side of the thermoelement; and

a second heat element disposed at a predetermined position of an interior or an

exterior of the printing machine,

the first heat element being connected to the second heat element via a heat

pipe.

8. The device of claim 7, wherein the thermoelement is disposed on a bottom

and/or a side of the supplying pan and/or the storing tank.

9. The device of claim 7, further comprising a heat sink and a blowing fan

at the heat sink.

11. The device of claim 7, wherein the first heat element is the heat pipe

embedded heat sink.

12. The device of claim 7, further comprising a blowing fan disposed at one